Apparatus for smoothing and polishing television panels and bulbs



Aug. 23, 1955 L. A. BEARD ETAL APPARATUS FOR SMOOTHING AND POLISHING TELEVISION PANELS AND BULBS 4 Sheets-Sheet l Filed Nov. l2, 1952 JAS Qw Y wh MWA,

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Aug. 23, 1955 A. BEARD ETAL APPARATUS FOR SMOOTHING AND POLISHING TELEVISION PANELS AND BULBS 4 Sheets-Sheet 2 Filed NOV. 12, 1952 INVENTORS 2. Base/ens,

HAE VEY Aug. 23, 1955 L. A. BEARD ETAL APPARATUS FOR SMOOTHING AND POLISHING TELEVISION PANELS AND BULBS 4 Sheets-Sheet 4 Filed Nov. l2, 1952 INVENToRs HARVEY e Base/lez,

s1/s A. 55420,

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United States Patent O APPARATUS FOR SMOOTHING AND POLISHING TELEVISION PANELS AND BULBS Lyle A. Beard, Knoxville, and Harvey R. Buskirk, Ulster, Pa.

Application November 12, 1952, Serial No. 319,940

Claims. (Cl. 51-3) This invention relates to an automatically operating apparatus designed particularly for polishing and smoothing the panels of television picture tubes.

In the art to which the invention relates, the manufacture of television picture tubes has reached large proportions, as a result of which the polishing and smoothing of the panels of said tubes has become an operation carried on on a large scale.

Despite the fact that the grinding and smoothing of said panels is a large scale operation, at present this particular step in the processing is carried out manually, with each panel being polished and smoothed by manual exertion on the part of a Worker.

rl'liis is obviously an undesirable situation, and considerable time and effort has been devoted to the design of an apparatus which will eliminate these manually carried out steps in the manufacture of a picture tube. However, to our knowledge, no apparatus which will be completely eflicient, within prescribed tolerances, has so far been designed.

The main object of the present invention is to provide an apparatus which will automatically polish and smooth the panels of television picture tubes, while said tubes are fed through the apparatus on a conveyor belt, in successively following order.

Another object of the invention is to provide an apparatus of the character referred to which, by reason of its automatic operation, will eliminate a substantial amount of the manual effort heretofore exerted in the polishing and smoothing of bulb panels, thus to permit said operations to be carried on with the expenditure of far less time and effort than is presently required.

Yet another object is to provide an apparatus of the character referred to which will be so designed as to permit the polishing and smoothing of picture tube panels both before said panels are assembled with tunnels to form a completed bulb, and after they are so assembled With tunnels This is of importance because, while the polishing and smoothing operations are normally carried out before the panels are fused with funnels to form the bulbs, said grinding and smoothing operations are also necessary, in many instances, after the panels and funnels have been formed into a bulb.

Another object of importance is to provide an apparatus in which the drums abrade or polish the tube panel with pumice over the entire area of the panel, despite the normal convexity of said panel.

Other objects will appear from the following description, the claims appended thereto, and from the annexed drawings, in which like references designate like parts throughout the several views, and wherein:

Figure l is a top plan view of an apparatus formed in accordance with the present invention, the end portions of said apparatus being broken away;

Figure 2 is a side elevational view;

Figure 3 is an enlarged transverse sectional view taken substantially on line 3-3 of Figure 1, showing the construction of one of the pumice application drums;

Patented Aug. 23, 1955 Figure 4 is a transverse sectional view, on an enlarged scale, taken substantially on line 4-4 of Figure 2, showing the construction of the rouging means;

Figure 5 is a sectional view through the rouging assembly, taken substantially on line 5-5 of Figure 2;

Figure 6 is an enlarged transverse sectional view taken substantially on line 6-6 of Figure 2, the full and dotted lines respectively showing alternate positions of a pair of conveyor belts, a supported television bulb being illustrated in dotted lines;

Figure 7 is a fragmentary perspective view of the conveyor belts; and

Figure 8 is a view partly in elevation and partly in longitudinal section of a modified form of pumice drum.

Referring to the drawings in detail, the reference numeral 10 has been applied generally to designate an elongated support frame, said frame being rigidly formed from suitable metal material, such as channels, I-beams, etc. welded or otherwise rigidly connected to provide a support for the moving parts of the apparatus.

In the illustrated example of the invention, the elongated support frame 10 is provided, at intervals spaced longitudinally thereof, with transversely extending cross members 12, said cross members 12 being supported upon a iloor or other supporting surface, to which the cross members can be bolted if desired.

Rigidly secured to the opposite ends of the several cross members l2 are lower longitudinal members 14, said longitudinal members 14 extending through the full length of the apparatus. Standards 16 are welded or otherwise rigidly joined at their lower ends to the members 14, at intervals spaced longitudinally of said members 14, the standards 16 being formed from channel iron material or the like.

To rigidity and strengthen the structure, angular braces 18 can be provided, said braces being welded at their opposite ends to the standards and members 14.

We believe that quite possibly, the particular formation of the supporting frame can be varied, it being mainly important that an elongated, raised structure be provided.

Extending the length of the apparatus is a conveyor, said conveyor including a pair of parallel belts adapted to support the work to be polished and smoothed. Each belt is carried by a conveyor belt support member 22, the member 22 being of channeled formation, and having a web 24 formed, at opposite longitudinal edges thereof, with depending side walls 26.

Each support member 22 is pivotally mounted upon the supporting frame 10, for movement from the horizontal position shown in Figure 4 to a tilted position. To this end, a pivot rod 28 is carried by upper longitudinal frame members 20, the pivot rod 2S associated with each support 22 extending in parallelism with the longitudinal ecnter line of said support, adjacent one side edge of the support.

Normally, the supports 22 are swung to a horizontal position shown in Figure 4, in which positions they support a plurality of television bulb panels P. ln effecting adjustments of the supports 22, any suitable means can be used, and the illustrated means comprises a plurality of adjusting screws 30 threadedly engaged in the upper longitudinal members 20. The members 3G, at each side of the support frame 10, are linked for joint rotation, thus to assure their uniform inward and outward movement.

To operate the several adjusting screws 30, a crank 32 can be provided upon one of said screws, said screw having a sprocket about which a chain is trained. Each of the several screws 30 has a sprocket 34 (see Figure 7), a single chain 36 extending about the several sprockets 34 at each side of the supporting frame 10. Y

By reason oi this arrangement. it will be seen that rotation of the crank handle 32 in one direction will be effective to simultaneously adjust the several screws 30 inwardly, against the adjacent. side well 26 ofthe conveyor Vbelt support niemberZZ.. This will hold the support meme ber in a selected position of Vtiltable adjustment, with position een be any tilted. or inclined position with respect to the horizontal position of the support member 22 shown in Figure 4. Y

lt is also desired that a positive means be provided for locking the .supports 22 in their horizontal positions.

To this end, .e plurality Of deterlts .3 8 can be mounted upon the respective longitudinal members 20, said detents being swingable upwardly and downwardly, and being spring urged to their up positions. The detents 38 have f notches. 4u at theirouter ends., receiving the adjacent side well Z6.V The detente. 38. when swung downwardly and out of engagement with the adjacent side walls. 26 of the The drums 58 .are spaced longitudinally of the apparatus, at the entrance end thereof and indicated by the letter A in Figures l and 2. As shown in Figure 2, the last drum 58, that is, that drum 58 most remote. from the entrance end, rotates oppositely to the direction of rotation ofV the other drums 58, it being found that this acts to clean 4 2 being of the endless web type. The web 24 of each Y and 7), having circumferential grooves 50 disposed rnedially between their ends, to accommodate the ribs 46 of the belts.

At each. end, the. conveyor belt support member z2 is, inL the illustrated embodiment of the invention, provided with projecting ears. 5,4 having openings receiving the op-` posite endg of theY roller 48, associated therewith.

1.1.1. View' Qf the. fact. that the entire conveyor belt assembly' is. tiltebly adjustable., it is necessaryv that the rollers 48 be tiltably swingable therewith, between the full and dotted. line .positions of thek rollers shown in Figure, 6g, Accordingly, i0. drive therollers, flexible .Shefting 52. is. used. "ibeshefting 52 is iournaled. at its enroute sides, ofthe supporting frame 10.

. A means for driving the. rollers 48. will be described l' hereinafter.

The: PILIRQSLQ Qf the. adjustable positioning of the conguter end, in bearing, plates 56. rigidly mounted upon verorbeltsisto. allowthe apparatus to. polish and smooth l not only panels. Ps, butconinleted bulbs. B.. In other wordsJ duringthe manufacture of a b u1b B, the panel P is processed through the grinding. and smoothing operations, before itis fused to a funnel. Subsequently. the panel is bonded to a funnel, to ferm. a. completed bnlb..B:. During the assembly of the panel and funnel, the panel may becomedisjgured, as a result of which selected bulbs B- are reprocessed through kthe apparatus. illustrated and described herein. When thel bulbs4 are reprocessed in this manner, the conyeyor belts are adjusted to their tilted positions so. as to. engage diametrically opposite portions of. the funnel portion of the. bulb, While still feeding the billblQDgllLldpllY Of: the. apparatus. The. screws 0f course, hold theA Conveyor beltsV in their selected posif iQuS Qf; f .ildble adjustment., sov as; te. support the bulbs B at a desired elevation during the polishing and smoothingY thereof.

Figures 12, and, 3 we have illustrated a means for implying. pumice; to. the panels or bulbs, said means in.. Cluding; a plurality of pumice drums designated: generally by the. reference, numeral 58 and eachcarriedby a. .horizontally disposed shaft 68 rotatingabove the conveyor.

the pumice from the panels or bulbs. Y

lt is important that the several drums 58 apply a constant pressure against the panels or bulbs passing thereunder. it being equally important, however, that the drums yield as necessary to conform the surfaces of the drums to the convexity of the panels P. VSaidconvexity is, of course, quite slight,rbut it nevertheless exists, and it is important that all areas of the panel P beV treated uniformly, with equal amounts of pumice being applied thereto and with equal pressure being imparted to the panel surface for the purpose of creating a uniform abrasive action thereon.

in view of the above, the drums 58 Vare specially` formed, and reference should now be had to Figures 2 and 3, wherein it is seen that each drum includes an outer cylinder 60 which, in one embodiment of the invention, can be of metal formation, said cylinder being of substantially greater diameter thanV and being normally concentric with an inner cylinder 62.

A circumferential series of springs 62 is provided, the springs of said series being interposed between the cylinders 6G, 62 respectively, thus. to normally hold the cylinders in concentric relation, while still permitting temporary shifting of one cylinder relative to the other into an eccentric relationship or into a position in which the cylinders have their axes in oblique. relation to one another, rather than'in their normal coaxial alignment.

Also provided in each drum 58 are springs 66,- said springs 66 being disposed in circumferential series spaced longitudinally of the drum, with the springs of said Y The opposite ends of each drum shaftl 68 are supported in upstanding extensions 70, said extensions, bein-g extended vertically from the upper ends of and being rigid with selected standards 16. The extensions 70 are of channeled formation,V and slidably mounted thereon are bearings 'Z2 in which the ends of the shafts 68 are journaled. The bearings 72 are thus utilized as floating bearings, so as to permit the drums 58 to be shifted bodily upwardly and downwardly.

Each bearing 72 is provided, at itsv outer: end, with a cylindrical extension, about which iscircumposed the annular clamp portion 74 provided at the lower endV of a piston rod 76 having a piston 78 working upwardly s and downwardly within a hydraulicgcylinder. A spring 82 may be interposed between ltheV lowerv end ofthe cylinderV andv the piston 78, so as to normallyl urge the piston 7 8 upwardly within the cylinder.

lines 84 are extended from a cornrrionV main hydraulic fluid supply line 86, which extends from'a suitablehy` draulic control mechanism, not shown.

Whe-nf fluid: isv suppl-fed under pressure to 'the severalY cylinders 80,- it willE be effective to force` the several pumice drums 58 downwardly, againstk the panels P-.g As a result, a substantial pressure is exertedl downwardly against the panels, soY as to cause saidpanels4 to Ybe effectivelyfjpolished whenthed'rurns arerotated. y,

It Will be understood, of' course,that' although' a substantial amount of pressure is exerted downwardly by the drums against the panels P, the drums are still so formed as to yield to a necessary extent, thus to prevent breakage of the panels while still assuring uniform coverage of all portions of the panel surface.

Disposed above each drum 58, and arranged longitudinally of the drum, is a pumice trough 88, each trough being supported, as shown in Figure 3, by trough support brackets 99 mounted upon the bearings 72. Since the troughs are supported by the bearings 72, they move upwardly and downwardly with their associated drums 58 as a unit, thus to keep the troughs in a particular, selected, spaced relationship to the drums.

The troughs 88, along their bottom edges, have a continuous longitudinal opening, through which pumice will gravitate, thus to cause the several drums 58 to be coated uniformly with pumice.

It is important, after the panels or bulbs have been processed through the series of drums 58, that they be properly polished by the drums, and to insure that the desired polishing action is obtained, we may desire, in certain instances, to vary the construction of the drums.

A possible alternative drum construction is illustrated in Figure 8, the drum of Figure 8 being designated generally by the reference numeral 92. In this form of the drum, the shaft 94 thereof is surrounded by a plurality of springs 96. The springs are arranged in a plurality of series, spaced longitudinally of the shaft 94, the springs of each series projecting radially from the shaft and being spaced circumferentially thereabout.

At their outer ends, the springs 96 are engaged against the inner surface of a metal cylinder 98, and adhesively or otherwise secured to the outer surface of said cylinder is a thick sponge rubber covering 100, about which is circumposed a wool cover 102.

The means for driving the several drums 58 will now be described, and reference should now be had to Figure 3, wherein it is shown that a drive motor 104 is mounted upon the support frame 10. Secured to the shaft of the motor 164 is a small drive pulley 106 about which is trained a drive belt 108, said belt 108 being tensioned by an idler 11G, and being trained about a large driven pulley 112. The driven pulley 112 is secured to one end of the shaft of one of the rollers 58, this being the middle roller when said rollers are viewed as in Figures l and 2.

Secured to the other end of the shaft of the middle roller or drum is a sprocket 114, about which is trained a chain 116.

As will be noted from Figure 2, the chain 116 extends longitudinally of the entire series of rollers 58, each roller being provided with a sprocket 114 engaged by said chain. However, the sprocket 114 of the innermost roller 58, that is, that roller shown at the right in Figure l, is disposed exteriorly of the endless chain 116, rather than interiorly thereof. As a result, the roller 58 shown at the righ'. in Figures l and 2 will rotate clockwise, while the other rollers 58 will rotate counter-clockwise.

It is necessary, after the panels or bulbs have passed beyond the last roller 58, that all pumice on the panels be cleaned therefrom, since any pumice that is allowed to remain upon the panel will be ground thereinto during a later step in the polishing and smoothing operation.

To accomplish the cleaning of the panel surfaces, we provide a sprocket 118 rotated by the chain 116. The sprocket 118 (see Figure 2) is secured to one end of the shaft of a wiping roller 120, said roller 120 being substantially smaller in diameter than the diameter of the rollers 58. The wiper roller 120 is formed of a soft material such as a soft, ne sponge, and is disposed directly in the path of jets of water discharged under substantial pressure from nozzles 122 spaced longitudinally of the wiping roller 121) (see Figure l). The nozzles 122 depend from a pipe 124 disposed transversely of and above the conveyor belts, the pipe 124 extending from one 6 end of a water supply pipe 126, to which water is fed under pressure through a connection 128.

It will thus be seen that simultaneously with the application of a substantial quantity of Water under pressure to the face of each panel P, after the panel has passed through the series of drums 58, the panel will be wiped clean. This, as will be apparent, will effectively remove all the pumice, so as to prepare the panels for the next step in the operation.

Below the nozzles 122, we provide a drain trough 129, which will receive the Water discharged from the nozzles.

Means is provided for driving the conveyor belt rollers, and to this end, a conveyor drive shaft 128 is journalled transversely of the support frame (see Figure 6). The shaft 128 is driven by a pulley 131), about which is trained a belt 132, it being understood that the belt 132 would be driven by a suitable motor, not shown.

Secured to the shaft 12S is a sprocket, about which is trained a chain 134, said chain 134 being trained about a sprocket secured to the outer end of one of the flexible shafts 52. A similar chain is secured to the other end of the shaft 128', so as to drive the corresponding conveyor roller at the other side of the apparatus.

So as to link adjacent conveyor rollers for joint operation, endless chains 136 are provided, said chains being meshed with sprockets carried by adjacent shafts 52.

As a next step in the polishing and smoothing operation, the panels P or bulbs B, as the case may be, are passed under a series of rotating, horizontally disposed rouging Wheels.

The rouging wheels constitute part of a smoothing assembly, said assembly including a hollow casing 138 (Figures 4 and 5).

Mounted rotatably upon the upper end wall of the casing 138 are collars 140, said collars being of hollow formation. Hydraulic fluid supply lines 142 extend in communication with the several collars 149, fluid being forced into said lines under pressure, from a main line 144. The main hydraulic fluid supply line 144 is controlled remotely by a suitable means, not shown.

The collars are secured to hollow shafts 146 rotatably mounted in the top wall of the casing 138, said hollow shafts extending downwardly into the casing and communicating with hollow spline shafts 148, rotatably mounted in bearings 150.

Secured to the several shafts 148, for rotation therewith, are sprockets 152, about which is trained a single endless chain 154 (Figure 5). Idlers 156 engage said chain, and are adjustable toward and away from the chain by means 158, thus to hold the chain under a selected tension.

A single dn've shaft 160 is used to power the chain, said shaft being provided with a bevel gear 162 (Figure 2) in mesh with a bevel gear carried by the shaft of a rouge wheel drive motor 164.

It will be seen that on operation of the motor 164, the several hollow shafts 148 will be driven simultaneously, in a common direction.

Carried by the shafts 148 are solid spline shafts, the shafts 148 having spline grooves receiving spline ribs of the shafts 168.

The spline shafts 168 are forced downwardly by the uid supplied under pressure to the portions of the several shafts 148 above the top ends of the spline shafts 168, thus to cause a uniform but substantial pressure to be applied to the surface of the panels P, during operation of the apparatus.

At the lower ends of the shafts 168, we provide universal connections 170, whereby there are movably connected to the shafts rouging discs 172. Thus, the discs 172 rotate conjointly with the several spline shafts 168, while being permitted, at the same time, swingable movement to selected positions, whereby said rouging discs will conform to the particular shape of the panel surface.

Each disc 172 is circumferentially grooved, to receive a rubber backing disc 174, said disc 174 having a felt pad 176 cemented thereto.

l Agitated'rouge is sprayed between the severalrouging .wheels, and to accomplish this action, we provide arouge tank 178 (Figures 1 and 2). The tank 178 is of sealed formation, withV air being supplied under pressure thereto through an air supply Vline 180.

The rouge is forced from the tank by the compressed air, through outlet lines 182, said lines ISZterminating in nozzles 184.

As will be noted from Figure 1, a second water supply Y. line 186 extends from the fitting 128, the line 186 terminating in a header 188 carrying a series of depending nozzles 190. Thus, after the panels or bulbs pass below and are polished by the wheels 176, waterjets under pressure will be sprayed thereagainst, to clean the rouge therefrom.

Thereafter, the Ypanels or bulbs pass to a drying means shown at the .right in Figures -l and 2. Said means includes a housing 192 formed with a plurality of air inlet openings 194. Mounted within the housing is Va blower Y including a series of blades 196, said blower being arranged to direct air past a resistance element 198, for heating of said air prior to impingement thereof against the panel or bulb.

The panels or bulbs enter the housing 192 through an opening 200, over which may be hung a flexible flap 202.

It will thus be seen that Ythe work, when passing throughV the housing 192, will be dried by warm air currents blown thereagainst.

The construction illustrated and described can, it is believed, be varied in certain respects, within the scope of the appended claims. For example, the particular Vnumber of pumice rollers and rouging wheels illustrated in the drawings is not critical, andcan be increased or decreased, as necessary. Y Y.

Additionally, it may be desired to use hair pads on the rouging wheels, rather than felt pads. Other changes,

of course, may be found desirable.

It is believed apparent Ythat the invention Vis not necesvsarily coniined to the specific use or uses thereof described above, since it may be utilized for any purpose to which it may be suited. Nor is the invention to be necessarily limited to the specific construction illustrated and described, since such construction is only intended to be illustrative of the principles of operation and the means presently devised to carry outY said principles, it being considered that the invention comprehends any minor Vchange in construction thatV may be permitted within the Vscope of Vthe appended claims.

What is-claimed is:

1. Apparatus for polishing and smoothing television picture tube panels and bulbs, comprising: a supporting frame; a conveyor supported thereon and' including a pair of side by side, endless belts tiltably adjustable VaboutV axes extending longitudinally thereof, between one position in whichsaid belts are aligned transverselyl of the frame in a common horizontal plane for supporting panels, and a second position in which the belts converge downwardly when viewed in cross section for supporting bulbs; means for holding the belts inrselected positions Y to which they are'tiltably adjustedya series of drums spaced longitudinally of the conveyor and each carried tiltably mounted on the frame for adjustment about axes extending longitudinally of said members between one position in which said members are aligned transversely of the frame ina common horizontal plane for supporting panels, and a second position in which the members converge downwardly when viewed in cross section Vfor supporting bulbs, endless belts mounted on said members, Y

and means for holding the members in selected position to which theyare tiltably adjusted; a series of drums spaced longitudinally of the conveyor and each carried by a horizontally disposed shaft rotating above the conveyor; means for cleaning said articles of pumice after passage thereof under said drums; a series of vertically disposedV shafts rotatably mounted above the conveyor and carrying at their lower ends discs arranged to polish saidV articles after movement thereof past said means; and means for, in succession, cleaning and drying the articles after passage .thereof beyond the discs. Y

3. Apparatus for polishing and Vsmoothing television picture tube panels and bulbs, comprising: a supporting frame; a conveyor supported thereon and including a pair of side by side, elongated, support member of inverted U shape in cross section, said members being tiltably mounted on the frame for adjustment about axes extending longitudinally of said members between one position in which said members lare aligned transversely of theV frame in a common horizontal plane for supporting panels, and a second position in which the members converge downwardly when viewed in cross section for supporting bulbs, belt rollers rotatably'mounted at opposite ends of the members, endless belts mounted on said members and driven by the rollers, said rollers having flexible shafts extending therefrom, means for driving the shafts, and means for holding the members in selected positions to which they are tiltably adjusted; a seriesof drums spaced longitudinally of the conveyor and each' carried by a horizontally disposedV shaft rotatably Y mounted above the conveyor; means for cleaning said panels'and bulbs of pumice after passage thereof under said drums; a series of vertically disposed shafts rotatably mounted above'the conveyor and carrying at their lower ends discs arranged to polish said panels and bulbs after I movement thereof past said cleaning means; and means for, in succession, cleaning and drying the panels and bulbs after passage thereof beyond the discs.

V4. Apparatus forpolishing and smoothing convexed picture tube V'panels and bulbs, comprising: a supporting frame; a conveyor supported thereon; a seriesV of drums spaced longitudinally of the conveyor and each carried by a horizontally disposed shaft rotatably mounted above Vthe conveyor and adapted to exert pressure against panels and bulbs passing thereunder while conforming to the convexity of the panels and bulbs, the shafts of said drums extending transversely of -theconveyor with the shaft disposed innermost vof said series of drums rotating in thev `direction opposite to the direction of rotation of the other shafts of the drums in such series; a pumice feed trough extending longitudinally of each drum immediately thereabove; means for cleaning said panels and bulbs of pumice after passage thereof under said drums; a series of vertically disposed shafts rotatably mounted above the conveyor and carrying at their lower ends discs arranged to polish said panels and bulbs after movement thereof past by a horizontally disposed shaft rotatably mounted above the conveyor; means for cleaning said articles of pumice after passage thereof under said drums; a series of vertically disposed shafts rotatably mounted above-the conveyor and carrying at their lower ends discs arranged to l polish said articles after movement thereof past said means; and means for, in succession, cleaning and drying the articles after passage thereof beyond the discs. Y

2. Apparatus for polishing and Vsmoothing television picture tube panels and bulbs, comprising: a supporting Yrframe; a conveyor supported thereon Vand including apair of side by side, elongated, conveyor support members said cleaning means; and means for, in succession, cleaning and drying the panels and bulbs after passage thereof 9 including a cylinder circurnposed about its shaft, and a plurality of springs interposed between the shaft and cylinder; a pumice feed trough extending longitudinally of each drum immediately thereabove; means for cleaning said panels and bulbs of pumice after passage thereof under said drums; cleaning means including a wiping drum disposed transversely of the conveyor and a plurality of spray nozzles disposed for directing spray jets against the wiping drum and at the opposite sides of said drum; a series of vertically disposed shafts rotatably mounted above the conveyor and carrying at their lower ends discs arranged to polish said panels and bulbs after movement thereof past said cleaning means; and means for, in succession, cleaning and drying the panels and bulbs after passage thereof beyond the discs.

References Cited in the iile of this patent UNITED STATES PATENTS Re. 18,533 Drake July 19, 1932 350,689 Marshall Oct. 12, 1886 1,583,807 Soderberg May 11, 1926 1,724,704 Fox Aug. 19, 1929 2,003,905 Schottland et al. June 4, 1935 2,021,371 Manchester Nov. 19, 1935 2,621,445 Wallace Dec. 16, 1952 

